1. Field of Invention
The present invention relates to a memory and a manufacturing method thereof, and more particularly, to a non-volatile memory and a manufacturing method thereof.
2. Description of Related Art
A non-volatile memory is able to retain the stored data even when the electrical power is off. As a result, many electronic products have such memories to provide normal operations when booted. In particular, a flash memory allows multiple data writing, reading, and erasing operations. With these advantages, the flash memory has become one of the most widely adopted memory devices in personal computers and electronic equipments.
Higher gate coupling ratio (GCR) and transconductance (Gm) are desired for a flash memory to enable the memory to have better performance. The gate coupling ratio and transconductance are associated with the inter-gate dielectric layer. The capacitance of the inter-gate dielectric layer can be increased as the inter-gate dielectric layer becomes thinner and the dielectric constant thereof gets higher. In addition, the gate coupling ratio can be increased as the area of the inter-gate dielectric layer becomes greater.
However, a thin inter-gate dielectric layer frequently results in the degradation of data retention. Further, a high dielectric constant (high-k) material is usually not compatible with the existing memory processes. Besides, the manufacturing process is difficult when the area of the inter-gate dielectric layer is increased. Therefore, how to effectively increase the gate coupling ratio and transconductance in the existing processes has become one of the main topics in the industry.